injector knock after turbo install?

[FORDF250HDXLT]

Truth of the matter is, any injector can go bad. Reman... new... whatever. Some are just more apt to do it based on what has been done with them. Your turning up the pump probably pushed one of them harder than it had seen in your previous driving, and you found a weak one. Problem is, it is only going to do it at speed, so you are going to need one more injector, and you will have to cycle your "known good test injector" through each hole until you can find the problem. Get yourself some new injector O-rings, because by the time you are done snapping caps on an off, you will need them. Fun stuff.

there's a much easier way.

you can find the bad injector using just your multi meter.it's a long thread on FTE but it's good read for those interested;
http://www.ford-trucks.com/forums/593483-using-glow-plugs-to-super-tune-the-engine.html

 

[Black dawg]

there's a much easier way.

you can find the bad injector using just your multi meter.it's a long thread on FTE but it's good read for those interested;
http://www.ford-trucks.com/forums/593483-using-glow-plugs-to-super-tune-the-engine.html

While I have used that method to find a dead hole, It is not nearly as easy as you would think it to be.

In this case, I would have someone rev on it, while I loosened each line. Wearing ear plugs of course. It is sometimes easier to have the person in the cab be the one listening for the knock to go away.

 

[bullfisher]

there's a much easier way.

you can find the bad injector using just your multi meter.it's a long thread on FTE but it's good read for those interested;
http://www.ford-trucks.com/forums/593483-using-glow-plugs-to-super-tune-the-engine.html

That's a good read and very interesting, but by page 5 it was already blowing my mind. As mentioned above I think I can use a variation of this to find the culprit cylinder.

 

[FORDF250HDXLT]

That's a good read and very interesting, but by page 5 it was already blowing my mind. As mentioned above I think I can use a variation of this to find the culprit cylinder.

Whew, I just got done reading all 29 pages of this thread. I have some GP readings to share and I will post them once I get home. This method helped my find my bad injector without even pulling any of them, so I am grateful for this knowledge.

OK, I'll start from the beginning:

I'm not an electronics guy. I used the 2u setting because I am stupid but the values are still accurate, the decimal is just a space or two off.

8.5 BTDC with bad #4 2u setting:

#1 - .88
#2 - .92
#3 - .84-.85
#4 - .67
#5 - .99
#6 - .94
#7 - .90
#8 - .90-.91

Replaced new #4 with old injector. I noticed my #2 line was leaking at the pump during testing. 2u setting.

#1 - .86
#2 - .97
#3 - .86
#4 - .78
#5 - .90
#6 - .95
#7 - .87-.88
#8 - .91

Replaced #4 with old injector @ 11.7 BTDC 2u setting:

#1 - .86
#2 - 1.02-1.03
#3 - .84
#4 - .79
#5 - .96
#6 - .97
#7 - .91
#8 - .91-.92

@ 10 BTDC 2u:

#1 - .84
#2 - 1.02-1.03
#3 - .81-.82
#4 - .75
#5 - .90
#6 - .95
#7 - .85
#8 - .91

@ 9.0 BTDC 2u:

#1 - .85-.86
#2 - .97
#3 - .82-.83
#4 - .72
#5 - .90
#6 - .92
#7 - .84-.85
#8 - .88

I have three more sets of values but I am not sure of the timing. I tossed the meter because at 8.5 BTDC it sounded retarded. I advanced it to where I thought it sounded right. I want to say 10.6 BTDC but I am going back a few weeks. I got the 21.83 MPG on my "custom" timing, though. Here are the readings I recorded at the time. 2u setting.

#1 - .90
#2 - 1.05
#3 - .91
#4 - .76
#5 - .97
#6 - 1.0
#7 - .97
#8 - .96-.97

I should be getting my new replacement #4 tomorrow and I will install it when I get home from work and take more readings.

2u | 2m settings #1-#8

.90 | .51
1.03 | .57
.86 | .48
.78 | .44
.96 | .53
.94 | .53
.99 | .55-.56
.90 | .50-.51

What does a millivolt sign look like on a multi-meter? Yeah, I'm dumb, I know. I wish I could find the manual for the thing!

Here are my GP readings after the new injector was installed:

#1 - .93
#2 - 1.06
#3 - .89
#4 - .93-.94
#5 - .86
#6 - 1.01
#7 - 1.0
#8 - .92

The truck runs smoothly now. I don't get any shaking at idle or in gear. I am very happy with these results. I can't wait to install a turbo and turn up the fuel. I should have good performance after that.

.......................................................

While I have used that method to find a dead hole, It is not nearly as easy as you would think it to be.

In this case, I would have someone rev on it, while I loosened each line. Wearing ear plugs of course. It is sometimes easier to have the person in the cab be the one listening for the knock to go away.

well you know the old saying; if it was easy,everyone would do it lol.but just how easy do you think it would be swapping an injector in every hole looking for it that way? personally,i would get out the meter and take a peek.

 

[bullfisher]

Great post fordf250hdxlt, thanks for sharing.

 

[Black dawg]

I am not against different ways to diagnose things, what works for one guy might not work for another. In this case, I gaurantee that disabling injectors would be quicker for me. I know this isnt relative to the OP, but around here, the meter would be pointless, as most of these old trucks have had burnt out glow plugs for years.

 

[riotwarrior]

Seems to me that ensuring all glow plugs are equally new and of same brand would be most ideal. Otherwise I could see running into issues that may be from old worn plugs or different brands providing skewed readings.

Interesting concept, I'm wondering if there is a realtime way of setting up a reading off the plugs and recording that other than multi meter...Hmm...

 

[BDCarrillo]

Seems to me that ensuring all glow plugs are equally new and of same brand would be most ideal. Otherwise I could see running into issues that may be from old worn plugs or different brands providing skewed readings.

Interesting concept, I'm wondering if there is a realtime way of setting up a reading off the plugs and recording that other than multi meter...Hmm...

No... not if you plan on using them to start the vehicle without a bunch of goofy high-amp relays and stuff. They have to be electrically isolated to test each cylinder individually, but obviously connected to start.

I like loosening the lines and watching how my beer sloshes in the bottle, sitting on the battery.

 

[Black dawg]

wouldnt you have to have a beer on both batteries for the test to be accurate?

 

[laserjock]

Okay. That's funny.

 

[bullfisher]

Decided to peak at the injectors tonight to see what they could tell me. Pic on the left is driver side. Pic on the right is passenger side. As you can see, I had one wet one on the ds and one clean on the ps. The rest where all the same.

 

[79jasper]

Could just be me, but the wet one seems like something is wrong with the pintle. Could be ******* fuel.

Sent from my SM-T537R4 using Tapatalk

 

[BDCarrillo]

Could just be me, but the wet one seems like something is wrong with the pintle. Could be ******* fuel.

Sent from my SM-T537R4 using Tapatalk

+1, looks goobered up

 

[bullfisher]

Well that's the last time I buy reman'd injectors. Luckily I hadn't sent back my original injectors which were fine. I was just replacing them while in there replacing my return lines. I did however, disassemble them and put them in my sonic cleaner. Took a test drive today and shes good to go so far. No smoke and a clean idle. I'll check the timing next but so far so good. Swapped in some new glow plugs whaile I was in there as well. One of the gp's was so deteriorated my 3/8 socket was to big for it and no matter what I did I couldn't keep it from snapping off flush with the head. But that's for another thread Thanks to everyone for your help and input.